Cleaning fluid



Patented Dec. 26, 1933 PATENT OFFICE CLEANING FLUID Arnold Mohn, St. Louis, Mo.,'assignor to Rhodes- Perry-Martin, Inc., St. Louis, Mo., a corporation of Missouri No Drawing. Application September 26,1929 Serial No. 395,476

2 Claims.

This invention relates to fluids of the character described, and more particularly to cleaning fluids adapted for use by dry cleaners.

When such a fluid is used in the cleaning of 5 clothes, fabrics and other articles, it is necessary to purify or reclaim the same. This is usually accomplished by distillation followed by condensation, as the foreign matter is thus left behind, so that the fluid canagaln be used.

One of the fluids which has been used to a great extent is carbon tetrachloride (CCLl), as it is a nonflammable solvent. Another fluid which is of great utility as a solvent adapted particularly for the cleaning of fabrics, etc., is ethylene dichloride 1 (CH2C1-CH2C1). While this solvent has a comparatively low fire hazard under ordinary conditions encountered at room temperatures, it will support combustion when ignited in the air, as its flash point in a closed cup is 14.4 C. (58 F.) and in an open cup is 14 C. (57 F.). As its boiling point is 83.5 C. (182.7 F.) there is a considerable fire hazard encountered in its distillation required for its recovery. While carbon tetrachloride has a boiling point of 768 0. (170 F.) it is nonflammable, as above stated.

Now, a mixture of carbon tetrachloride and ethylene dichloride is a highly satisfactory solvent. However, if no regard is had for the relative proportions of the components of the mixture, it is found that towards the end of the distillation period, the vapor becomes inflammable, thereby increasing the fire hazard and rendering the mixture dangerous to employ and particularly recover by distillation, where the cleaning establishment is in a business district.

One of the objects of this invention, therefore, is to provide a composition or fluid of the character described composed of ethylene dichloride and carbon tetrachloride, in which the components of the mixture are such as to be capable of distillation under nonflammable and nonexplosive conditions.

Further objects will appear from the detail description, in which will be given an illustrative embodiment of this invention; it will be understood, however, that this invention is susceptible of various embodiments without departing from the spirit thereof.

I have found that a composition or mixture composed of not more than 37.5%-40.5% by volume of ethylene dichloride, and not less than 59.5%- 62.5% by volume of carbon tetrachloride, has the desirable characteristics, in that such a mixture is capable of distillation under nonflammable and nonexplosive conditions. This is believed to be accounted for by the following properties:

The latent heat of vaporization of ethylene dichloride is 875 calories per kilogram, while the latent heat of vaporization of carbon tetrachloride is 46.6 calories per kilogram. These latent heats are, therefore, in the proportion of'1:1.87. Therefore, carbon tetrachloride evaporates 1.87 times faster than ethylene dichloride; accordingly, in a mixture of 1 part ethylene dichloride and 1.87 parts carbon tetrachloride (by weight), the two components require the same length of time for complete evaporation. Such a mixture contains 35% by weight or 40.5% by volume of ethylene dichloride, and by weight or 59.5% by volume of carbon tetrachloride; the specific gravities being taken as 1.26 for ethylene dichloride and 1.6 for carbon tetrachloride. Actual experiments show that mixtures containing up to 37.5% by volume of ethylene dichloride are neither inflammable nor explosive at any stage of distillation and recovery by condensation, as carried out in ordinary apparatus.

While this invention is particularly applicable to cleaning fluids, it will be understood that it is applicable in many cases to other compositions adapted for other uses. It will furthermore be understood that various changes may be made in the proportions, within the scope of the appended claims, without departing from the spirit of this invention. It is, therefore, to be understood that this invention is not to be limited to the specific uses and proportions described.

Having thus described the invention, what is claimed is:

1. A cleaning fluid capable of distillationunder non-flammable and non-explosive conditions and composed of not more than 37.5%-40.5% by volume of ethylene dichloride and not less than 59.5%-62.5% by volume of carbon tetrachloride.

2. A -cleaning fluid composed of ethylene dichloride and carbon tetrachloride in relative quantities substantially in inverse proportion to their latent heats of vaporization.

ARNOLD MOHN. 

